Northeastern's science team heads to Florida for Mission 31 on June 16, and we are all getting really excited to jump in to the fun. The planning for Mission 31 science has been happening for over a year, but for me the countdown officially began as soon as Liz returned from Aquanaut training. Since then, in addition to testing equipment, finalizing experiments, and making sure all of our dive gear is in working order, my days have been long and jam-packed with our own Mission-31 dive training, which includes lectures, exams, and a number of dives. Liz is incredibly intelligent and knows just about all there is to know about SCUBA- it’s an honor having such an awesome female scientist representing the NU team in saturation! But training has only been part of the M-31 prep… we need to plan for science too!I’m leading a project on the bioenergetics of the giant barrel sponge, Xestospongia muta. Sponges are seriously ancient, in more ways than one. Sponges as a taxonomic group may have been the first animals on the planet, and fossil sponges dating from 635 Million years ago have been found. Work by Joe Pawlik's group at UNC Wilmington also suggests that individual sponges can be as old as 2000 years, making them true "redwoods of the reef." During our two-week mission, we will continuously monitor pumping activity, respiration rate, and feeding rate in a number of these organisms. These in situ (in the field) measurements of metabolic (body fuel burning) activity taken continuously over a relatively long period of time will help us understand the mechanisms driving the flow of energy through these organisms, as well as how natural fluctuations in the environment can impact this flow of energy. Specifically, we want to know how much energy goes into respiration, growth, and repair and replacement of cells. In a nutshell, we are trying to understand how these organisms allocate energy they receive from their food, and to better understand how global climate change may affect these ancient organisms. Sponges may provide a significant amount of energy to organisms higher up the food chain, and are essential recyclers of nutrients on the reef. In fact, all of the water on a reef passes through the body of a sponge every 24-48 hours! So, understanding how the environment impacts the flow of energy through sponges also gives us insight on how environmental change may impact the functioning of the entire reef.

Giant Barrel Sponge: they are known as the Redwoods of the sea. They can live hundreds of years...and they are red. (photo by NOAA photo library)

We just received our brand new HOBO Dissolved Oxygen (DO) Loggers in the mail (yeah!), so for now I’ll just focus on how I plan to measure one of the metabolic processes mentioned above: Respiration Rate.

During the mission, we will measure rate of oxygen uptake, i.e. the amount of oxygen removed by the sponge per unit time. Throughout the mission, two sponges at a time will each be equipped with a YSI water quality sonde, which will measure dissolved oxygen (as well as many other parameters) in the excurrent flow of the sponge (in the barrel of the sponge).

YSI EXO2 sonde Water Quality Sonde: This fancy piece of equipment usually lives bolted to a rock on Pump House Beach, where it continuously measures water quality in a rocky intertidal shore right outside the Marine Science Center in Nahant, MA. But it's making the trip to FL with us for Mission 31, where it will be used to understand metabolic activity of the giant barrel sponge.

﻿We will additionally deploy an Onset Corporation dissolved oxygen logger near the sponge’s incurrent flow (the outside of the sponge) to measure the available surrounding dissolved oxygen. This way, by comparing oxygen measurements from inside and outside of the sponge we will be able to calculate the amount of oxygen removed from ambient water per unit time (i.e. respiration rate!) ﻿

We will deploy HOBO Dissolved Oxygen (DO) Loggers like this one near the incurrent flow of the sponges. Measurements of ambient DO, along with measurements of DO in the excurrent flow, will allow us to calculate respiration rate (amount of oxygen removed per unit time).

T-minus 11 days until we leave, and I am only getting more excited! I’m also a little nervous, though. For one, some of the equipment we are bringing with us is brand new, expensive, and I have never used it before. Brian and Mark have used this kind of equipment lots before and say that when you put expensive toys out into the ocean you just need to hope for the best and count on occasional losses, but this is all pretty new to me. I think I will bring a couple of the DO loggers with me on one of our upcoming dives in Nahant to make sure I am comfortable using them in the field.

The Northeastern team manages to carve out some time for fun, too :) Too bad Nick Colvard (far right) can't be here with us in MA during the countdown to NU splashdown... but I'm sure honeymooning in Greece isn't too terrible of an alternative ;)

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THe nu Surface Team﻿

We are graduate students and faculty from the Marine Science Center at Northeastern University. We will be sharing our personal daily Mission 31 experiences here! Visit northeastern.edu/mission31 to learn more about who we are and about the science that we will be doing with Fabien during the second half of Mission 31.